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10 votes
1 answer
151 views

For what $n$ do there exist non-periodic tilings with rotational symmetry of order $n$?

More precisely, given an integer $n$, does there exist a non-periodic tiling, where there are infinitely many patches within the tiling, of indefinitely large area, with rotational symmetry of order $...
Andrew Bayly's user avatar
20 votes
1 answer
2k views

Can you see through a cannonball packing?

More precisely, in a regular sphere packing, either the HCP or FCC lattice packing, does there exist a line $L$ disjoint from every sphere, i.e., not touching any sphere? If so, one could "look ...
Joseph O'Rourke's user avatar
1 vote
0 answers
56 views

Tiling with one of each 3D shape

Encouraged by the positive solutions to my question, Tiling with one of each shape, I'd like to pose the $\mathbb{R}^3$ equivalent: Q. Is there a tiling of $\mathbb{R}^3$ by (bounded) polyhedra, one ...
Joseph O'Rourke's user avatar
2 votes
1 answer
235 views

Tiling with one of each shape

Q. Is there a tiling of the plane by one each of simple polygons of $n$ vertices: one triangle, one quadrilateral, one pentagon, $\ldots$ , one simple polygon of $n$ vertices, $\ldots$ ? Here a ...
Joseph O'Rourke's user avatar
0 votes
1 answer
98 views

Chromatic tiling complexity and the chromatic number conjecture

Let $T$ be a finite set of tiles in $\mathbb{R}^d$. A tiling of $\mathbb{R}^d$ by $T$ is a collection of disjoint translates of tiles in $T$ whose union is $\mathbb{R}^d$. A tiling is $k$-chromatic if ...
Vincenco Fedor's user avatar
2 votes
0 answers
62 views

On convex polygons that can be cut into convex and mutually congruent pieces in exactly one way

Observations: any thin isosceles triangle has exactly 1 partition into 2 congruent pieces - only 1 line, bisector of its apex, does it. By attaching a right triangle with base 1 and altitude 2 to an ...
Nandakumar R's user avatar
  • 5,979
2 votes
2 answers
226 views

On cutting tetrahedrons into mutually congruent pieces

Simple observations: A regular tetrahedron can be cut into 2 mutually congruent pieces (in 3 obvious ways which are all basically the same way, giving one and same pair of congruent pieces). The ...
Nandakumar R's user avatar
  • 5,979
0 votes
0 answers
78 views

Are there triangles that can be cut into 7 mutually congruent connected polygons?

First question below had appeared in a note at Triangles that can be cut into mutually congruent and non-convex polygons Following the results of Beeson quoted in the answer at Subdivision of ...
Nandakumar R's user avatar
  • 5,979
9 votes
1 answer
542 views

Tracking a reference: "Karl Scherer, A Puzzling Journey to the Reptiles and Related Animals"

I linked a paper by James Schmerl in a recent question which cites Karl Scherer, A Puzzling Journey to the Reptiles and Related Animals, Privately Published, 1987. I have had difficulty finding any ...
Kepler's Triangle's user avatar
15 votes
1 answer
528 views

Dividing a polyhedron into two similar copies

The paper Dividing a polygon into two similar polygons proves that there are only three families of polygons that are irrep-2-tiles (can be subdivided into similar copies of the original). Right ...
Kepler's Triangle's user avatar
1 vote
0 answers
52 views

'Self-similar and perfect' partitions of planar regions

Definition: A partition of a planar figure into finitely many pieces that are all similar to itself and also mutually non-congruent may be called a self-similar perfect partition. A classical example ...
Nandakumar R's user avatar
  • 5,979
4 votes
1 answer
438 views

Perfect squaring of rectangles

A perfect squaring of a rectangle may be defined as a partition of the rectangle into finitely many squares all of which are mutually non-congruent. https://en.wikipedia.org/wiki/Squaring_the_square ...
Nandakumar R's user avatar
  • 5,979
0 votes
0 answers
41 views

Trying to extend a theorem on Tiling with mutually non-congruent triangles

In the light of Cubing the cube - as 'perfectly' as possible, We try to slightly 'relax' the main theorem proved by Kupaavski, Pach and Tardos here: https://arxiv.org/pdf/1711.04504.pdf ...
Nandakumar R's user avatar
  • 5,979
9 votes
0 answers
186 views

Cubing the cube - as 'perfectly' as possible

Ref: https://en.wikipedia.org/wiki/Squaring_the_square A perfect cubing of a cube is a partition of the cube into some finite number of smaller cubes that are pair-wise non-congruent. The above page ...
Nandakumar R's user avatar
  • 5,979
4 votes
0 answers
138 views

Hyponontiling Wang tiles

Call a finite collection of tiles that can tile the plane if we have to use each tile at least once tiling. Is there a collection of at least 3 tiles that is not tiling, but such that after removing ...
domotorp's user avatar
  • 18.7k
1 vote
1 answer
98 views

To place copies of a planar convex region such that number of 'contacts' among them is maximized

A contact between two planar convex regions obviously happens either along a line segment or at a single point. Question: Given a planar convex region $C$ and a number $n$, we need to lay out $n$ ...
Nandakumar R's user avatar
  • 5,979
1 vote
0 answers
92 views

Can a square be cut into non-right triangles that are mutually similar and pair-wise noncongruent?

We add a bit to Tiling the plane with pair-wise non-congruent and mutually similar triangles and Cutting polygons into mutually similar and non-congruent pieces A (non square) rectangle can obviously ...
Nandakumar R's user avatar
  • 5,979
4 votes
0 answers
175 views

Can a square be partitioned into mutually non-congruent triangles all of same area and perimeter?

It is known that the plane cannot be tiled by pair-wise non-congruent triangles all having same area and same perimeter (https://arxiv.org/abs/1711.04504). Question: Can a square be partitioned into ...
Nandakumar R's user avatar
  • 5,979
1 vote
0 answers
78 views

To tile the plane with mutually non-congruent rational triangles of equal area

We add a little to Tiling the plane with pairwise non-congruent rational triangles Question: Can the plane be tiled by pair-wise non-congruent rational triangles all of which have same area? If "...
Nandakumar R's user avatar
  • 5,979
2 votes
0 answers
73 views

Is this an actual solution for centroidal Voronoi tiling, or just a visual approximation? [closed]

For the capstone project at the end of my graduate Data Science studies in late 2022, I needed an algorithm that would converge to something close to centroidal Voronoi tiling, while tiling contiguous ...
Florin Andrei's user avatar
1 vote
0 answers
52 views

Does a substitution tiling being FLC depend on starting seed?

I've been trying to understand more on "geometric" substitutions rather than just symbolic ones. As symbolic substitutions always yield FLC tilings, I wanted to know whether a tiling coming ...
Keen-ameteur's user avatar
1 vote
1 answer
138 views

Recognizability/unique composition property for substitution tiling

This may be a very basic question, but I have not found an answer to it so far in my search. The question is whether there is an "algorithmic" way to check unique-composition/recognizability ...
Keen-ameteur's user avatar
12 votes
0 answers
168 views

Can the optimal packing density in $\mathbb{Z}^d$ be irrational?

For a finite $S \subset \mathbb{Z}^d$, let $d_p(S)$ be its optimal packing density. That is, the maximal lower asymptotic density of $A+S$, where $A \subset \mathbb{Z}^d$ is such that $(a_1+S)\cap (...
Arsenii Sagdeev's user avatar
7 votes
1 answer
248 views

Decidability of completing Penrose tilings

Is the following problem known to be un/decidable? Problem: Given a finite configuration of Penrose tiles in the plane, determine if there is an extension of the configuration tiling the whole plane.
interstice's user avatar
0 votes
1 answer
98 views

Tiling the plane with quadrilaterals that are mutually non-congruent and affine equivalent

Question: Can the plane be tiled with convex quadrilaterals that are (1) mutually non-congruent in a Euclidean sense and (2) mutually affine-equivalent? Remark: Every trapezoid is affine equivalent to ...
Nandakumar R's user avatar
  • 5,979
1 vote
0 answers
97 views

Tiling the plane with pair-wise non-congruent and mutually similar triangles

Question: Is it possible to tile the plane with triangles that are (1) mutually similar, (2) pairwise non-congruent and (3)non-right? No other constraints. Note 1: Reg requirement 3 above: since any ...
Nandakumar R's user avatar
  • 5,979
9 votes
4 answers
1k views

Tiling the plane with pairwise non-congruent rational triangles

A rational triangle is one in which all side lengths are rational numbers. Question: Can we tile the Euclidean plane with rational triangles that are pairwise non-congruent? No further requirements on ...
Nandakumar R's user avatar
  • 5,979
6 votes
1 answer
435 views

On the aperiodic monotile

One of the more mind-boggling aspects of the Penrose tiles is that there are uncountably many distinct tilings of the plane, but every tiling contains every finite region that appears in another ...
Jim Conant's user avatar
  • 4,898
17 votes
1 answer
580 views

Aperiodic monotile in $\mathbb{R}$

Motivation. Recently a group of researchers found an aperiodic monotile in $\mathbb{R}^2$, answering a long-standing question. There are many results in higher dimensions, so let's explore the lower ...
Dominic van der Zypen's user avatar
1 vote
0 answers
37 views

Tiling the hyperbolic plane with mutually-non congruent equal area triangles

This post continues On tiling the plane with non-congruent, equal area triangles with each edge having a unique length Can the hyperbolic plane be tiled by pair-wise non-congruent equal area ...
Nandakumar R's user avatar
  • 5,979
1 vote
0 answers
46 views

Kissing behavior of planar regions

This post reworks a question that was stated in a slightly different form at Convex region $C$ with least kissing number of copies of $C$. Background: Given a 2D region $C$ (not necessarily convex), ...
Nandakumar R's user avatar
  • 5,979
8 votes
1 answer
248 views

For which $n$ does a y-formed $n$-polyomino tile a $n \times n \times n$-cube?

I got from my children as a gift a puzzle consisting of 25 y-shaped 5-polyominoes that form a $5 \times 5 \times 5$-cube (see picture). I'm wondering for which $n$ does a y-formed $n$-polyomino tile a ...
Andreas Rüdinger's user avatar
5 votes
1 answer
397 views

How much of an aperiodic tiling is needed to force aperiodicity?

Consider an aperiodic tiling. By definition, there is a $C$ such that, for any box of side $C$, the part of the tiling contained in the box can be continued to the whole plane only in a non-periodic ...
H A Helfgott's user avatar
  • 20.1k
15 votes
2 answers
778 views

How to characterize the regularity of a polygon?

In my research, I've recently started to play with Voronoi tessellations. I currently have a Python code that creates the tessellation and I am trying to color the polygonal regions according to their ...
Caio Tomás's user avatar
7 votes
0 answers
87 views

Tiling the plane with mutually non-congruent equal area rectangles

Question: Is it possible to tile the plane with mutually non-congruent rectangles all of equal area? Note 1: If the answer is "yes" then, there could be constrained versions of the question ...
Nandakumar R's user avatar
  • 5,979
6 votes
2 answers
215 views

Partition of polygons into 'strongly acute' and 'strongly obtuse' triangles

Definition: Let us refer to obtuse triangles with the largest angle strictly above a given cutoff value as 'strongly obtuse' - the definition is parametrized by the cutoff value. Likewise, strongly ...
Nandakumar R's user avatar
  • 5,979
3 votes
1 answer
230 views

Tiling planar integer lattice by finite point sets

I am interested in the following question. Are there nice characterizations of the finite sets $S\subseteq \mathbb{Z}\times\mathbb{Z}$ that tile $ \mathbb{Z}\times\mathbb{Z}$ by translations (i.e. $\...
Pritam Majumder's user avatar
2 votes
0 answers
208 views

Aperiodic tilings of the plane by squares and rhombi

Consider tilings of the plane by unit squares and by rhombi of unit side length and angles $\pi/3$, $2\pi/3$. It is easy to come up with periodic tilings of the plane - consider the following: (from ...
H A Helfgott's user avatar
  • 20.1k
2 votes
0 answers
171 views

Square-and-equilateral-triangle aperiodic tiling with $\leq 4$ prototiles?

There exist aperiodic tilings composed of square and equilateral-triangle tiles of unit side length: see https://tilings.math.uni-bielefeld.de/substitution/square-triangle/ and https://hal.archives-...
H A Helfgott's user avatar
  • 20.1k
1 vote
0 answers
62 views

What are some other methods for partitioning an n-dimensional space based on a set of points in that space?

So this is a very general question, but I'm curious if there are any other methods for partitioning an n-dimensional space based on the location of a set of points, either randomly chosen or specified,...
Fran's user avatar
  • 11
25 votes
1 answer
2k views

Polyomino that can tile itself

Find all polyomino $P$ such that we can tile $nP$ with $n^2$ copies of $P$ for all $n\in \mathbb{N}$. ($nP$ is a polynomino similar to $P$ with scale factor $n$) I conjecture that there are only $4$ ...
Veronica Phan's user avatar
2 votes
0 answers
78 views

Tiling with triangles with same Steiner ellipses

We continue from Tiling with triangles of same circumradius and inradius . Definitions: Given any triangle, its Steiner circumellipse is the unique circumellipse (ellipse that touches the triangle at ...
Nandakumar R's user avatar
  • 5,979
42 votes
2 answers
2k views

Does any set of dominoes tile some common figure?

Let $D_1,\dots,D_n \subset \mathbb{Z}^2$ be two-point sets, i.e. 'dominoes' (unlike common dominoes, these are not necessarily connected, but I couldn't come up with a better name). Does there always ...
Arsenii Sagdeev's user avatar
3 votes
1 answer
152 views

Triangles that can be cut into mutually congruent and non-convex polygons

It is easy to note that an equilateral triangle can be cut into 3 mutually congruent and non-convex polygons (replace the 3 lines meeting at centroid and separating out the 3 congruent quadrilaterals ...
Nandakumar R's user avatar
  • 5,979
1 vote
0 answers
40 views

Tiling with a one-parameter family of non-congruent triangles

This post continues Tiling with triangles of same circumradius and inradius. The following are known about infinite sets of triangles that can be parametrized with one variable: from an infinite set ...
Nandakumar R's user avatar
  • 5,979
5 votes
0 answers
177 views

Tiling with triangles of same circumradius and inradius

Consider a pair of positive real numbers $r$ and $R$ with $r<R/2$. Then we can form infinitely many triangles all with circumradius $R$ and inradius $r$. For any such pair, the resulting triangles ...
Nandakumar R's user avatar
  • 5,979
24 votes
3 answers
3k views

Polyomino that can cover an arbitrarily large square but not the entire plane

https://userpages.monmouth.com/~colonel/nrectcover/index.html For a polyomino with no holes that cannot tile the plane, we may ask what are the maximal rectangles and infinite strips that it can ...
trotzt's user avatar
  • 359
7 votes
0 answers
227 views

Tiling space with supertile of hypercube unfoldings

Two students in my class asked and answered what might be a novel question. It is well known that the cube has exactly $11$ edge-unfoldings (or "nets"), as shown below:         (Image from ...
Joseph O'Rourke's user avatar
2 votes
1 answer
145 views

Automorphism group of a normal tiling of the plane

A normal tiling of the plane is a tessellation for which every tile is topologically equivalent to a disk, the intersection of any two tiles is a connected set or the empty set, and all tiles are ...
Arun 's user avatar
  • 745
4 votes
2 answers
432 views

Family of shapes that can be tiled into one another

Okay, I'm trying to ask a question which hasn't been asked before, it may be futile, but let's see. So let's take a square, this will be our shape A. We can tile a 2x1 rectangle by using shapes ...
Dr.X's user avatar
  • 89